Support arrangement for a continuous casting with drawing bolt and head

ABSTRACT

In commencing a continuous casting operation where the strand is conducted along an arcuate, deflecting or vertical path from the mold, a withdrawing bolt and head is positioned within the mold and is withdrawn with the strand through a support arrangement adapted to the cross-section of the strand being cast. As it passes through the support arrangement, the withdrawing bolt and head is pressed against spaced, fixed support rollers in the support arrangement by adjustable pressure rollers which are released from contact with the withdrawing bolt and head when the head begins to pass the pressure roller.

United States Patent [191 Baumann et al.

[ Mar. 12, 1974 SUPPORT ARRANGEMENT FOR A CONTINUOUS CASTING WITH DRAWINBOLT AND I-IEAD [75] Inventors: Hans G. Baumann; Wilhelm Koch,

both of Duisburg, Germany [73] Assignee: Demag Aktiengesellschaft,Duisburg,

Germany [22] Filed: June 22, 1971 [21] Appl. No.: 155,562

[52] US. Cl. 164/282, 164/82 [51] Int. Cl B22d 11/12 [58] Field ofSearch 164/82, 274, 282

[56] Y References Cited UNITED STATES PATENTS 3,550,675 12/1970 Hess etal. 164/282 3,638,713 2/1972 Knell 3,645,323 2/1972 Vogt et a1. 164/282FOREIGN PATENTS OR APPLICATIONS France 164/282 10/1969 Germany 164/2742/1969 U.S.S.R 164/274 Primary Examiner-R. Spencer Annear Attorney,Agent, or Firm-Toren and McGeady ABS'I RACT In commencing a continuouscasting operation where the strand is conducted along an arcuate,deflecting or vertical path from the mold, a withdrawing bolt and headis positioned within the mold and is withdrawn with the strand through asupport arrangement adapted to the cross-section of the strand beingcast. As it passes through the support arrangement, the withdrawing boltand head is pressed against spaced, fixed support rollers in the supportarrangement by adjustable pressure rollers which are released fromcontact with the withdrawing bolt and head when the head begins to passthe pressure roller.

1 Claim, 1 Drawing Figure Pmmaoum m4 3796252 /0 Veil/m:

HANS 66% NN WILHELM K SUPPORT ARRANGEMENT FOR A CONTINUOUS CASTING WITHDRAWING BOLT AND HEAD SUMMARY OF THE INVENTION The present invention isdirected to a support arrangement located at the outlet from acontinuous casting mold and, more particularly, it concerns a method ofand an apparatus for supporting a withdrawing bolt and head as itwithdraws a cast strand from the continuous casting mold. Further, theinvention is especially directed to arcuate, deflecting and verticalcontinuous casting plants.

In continuous casting operations, special care must be taken incommencing the casting operation because of the molten condition of thecore within the casting as it is withdrawn from the mold. Prior tocommencing the casting operations from the continuous casting mold,which mold is open at its top and its-bottom, a withdrawing head andbolt is positioned with the head inserted into the bottom end of themold and the head has a cross-section which fits closely within thebottom opening within the mold. The means for withdrawing the casting orstrand from the mold is located at some distance from the outlet of themold. In order to start withdrawing the strand from the mold, the boltportion of the withdrawing head and bolt extends from the head to thewithdrawing means and this length may be as much as ten meters or more.in effect, the bolt portion acts as an artificial or dummy casting incommencing the removal of the casting from the mold.

In a continuous casting plant where a large variety of sizes of moldsare used, a corresponding number of withdrawing heads and bolts arerequired. The storage of the continuous casting molds when not in useinvolves a considerable investment in space as well as in highmaintenance costs. To these costs must be added the correspondinginvestment in space and maintenance for the withdrawing heads and bolts.The size of these withdrawing heads and bolts dictates the size of apart of the continuous casting plant in which they are stored until theyare used again. In an attempt to solve this problem, a singlewithdrawing head and bolt has been used which has the dimensions of thesmallest casting cross-section to be produced. However, it is stillnecessary to provide the head portion of this piece of equipment withthe dimensions of the outlet from the mold cavity in the continuouscasting mold. The transition from the casting cross-section to the shapeof the starting casting is represented by inclined surfaces,accordingly, the head part of the withdrawing head and bolt has aconical or tapered configuration. Conically shaped heads and bolts areless expensive than most of the members used for commencing the castingswhich have different cross-sections. The starting members for suchcontinuous casting operations are favorable only in a very heavy form,that is when the weight of the withdrawing head and bolt is such that itcauses the head and bolt to press against the radially outer side of theroller guide track utilized in arcuate continuous casting plants forguiding the casting from the mold. It is only when the withdrawing headand bolt has considerable weight that an orderly or effective feed fromthe mold can be provided. When a lighter withdrawing head and bolt isused, it will separate itself from the support arrangement and then willmove back toward the support thereby causing an irregular or jerkytransmission of the feeding or withdrawing force to the cast- Duringstartup, there is the possibility that excessive loads will be placed onthe casting as it is initially withdrawn from the mold with the resultthat the solid casting shell cannot stand the applied stress in therange of the secondary cooling zone so that the casting will be at leastconsiderably damaged at the outset. Due to'irnproper removal, theleading end of the casting may develop either/or both internal andexternal defects so that it must be remelted for effective use. Whenthis occurs the percentage yield from the casting operation is not onlyreduced but additional costs are involved in the special handling ortreatment which must be given the casting. Under extreme circumstances,a strong pull on the casting can result in a rupture of its shell withits liquid core flowing outwardly through the rupture and contactingvarious parts of the casting plant. When such an accident occurs, thecasting process must be stopped and the plant is taken out of operationfor at least several hours if not for a period of days. Further, such anaccident can entail considerable costs to the casting plant itself. Whenthe casting process is discontinued, the melt ready to be used must bepoured into standby casting molds and an unplanned change in the plantoperation is necessary and must be effected without delay to avoidtemperature losses in the metal being cast. Accordingly, the advantagesgained by the use of the conical withdrawing heads and bolts is offsetby the difficulties experienced in properly withdrawing the casting fromthe mold.

Therefore, it is the primary object of the present invention to effectthe safe removal of the withdrawing head and bolt of a specialtypeincluding a conical head where the disadvantages and risksexperienced in the past are overcome and the withdrawing head and boltare adequately supported during removal against the development of anymovement or forces which would have a deleterious effect on the casting.In accordance with the present invention, a withdrawing head and bolt ofany cross-sectional dimension can be used as long as it is smaller thanthe cross-section of the casting to be removed from the mold andconducted along a supporting roller track which is adapted to thecrosssection of the strand being cast. On the radially outer side of thesupport arrangement, that is where an arcuate casting plant is involved,the withdrawing head and bolt is supported against a fixed set ofsupporting rollers, while on the opposite surface adjustable pressurerollers contact the surface of the withdrawing head and bolt andmaintain it in contact with the fixed supporting rollers. Due to theadjustable character of the pressure .rollers they can be withdrawn fromcontact as the head of the withdrawing head and bolt begins to pass thepoint of application of the pressure roller. In contrast to previouslyused methods, the thickness of the bolt portion of the withdrawing headand bolt plays, only a both the withdrawing head and bolt and thecasting are located within the roller support arrangement and thetransfer from the withdrawinghead to the casting can be effected withoutcritical periods. In accordance with this withdrawing arrangement, thecasting travels in an uniform, even manner and the load applied to it isalso uniform in all sections without any peaks.

In accordance with the invention, the structure for carrying out thewithdrawingoperation includes a supporting roller track set for thetransverse cross-section of the continuous casting. On one side of thetrack a plurality of spaced rollers are arranged to support, first, thewithdrawing head and bolt and, then, the casting, while on the oppositeside in addition to the rollers for the casting, adjustable pressurerollers and/or frames are provided which can be positioned to contactthe smallest cross-section of the withdrawing head and bolt. It is notimportant whether the adjustable pressure rollers are located in thesecondary cooling zone or downstream from this zone. With the adjustablepressure rollers located in the supporting roller track downstream fromthe continuous casting mold it is possible to provide a practicallyeffective manner of instituting the action of withdrawing the continuouscasting from its mold.

The various features of novelty which characterize the invention arepointed out with'particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be has to the accompanying drawings and descriptivematter in which there are illustrated and described preferredembodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic side view ofan arcuate continuous casting plant.

DETAILED DESCRIPTION OF THE INVENTION In the drawing a continuouscasting mold l is located at the upper end of an arcuate supportingroller track having a lower additional section 3 through which thecontinuous casting passes downwardly from the mold. The drawing displaysthe arrangement of the mold and supporting roller track arranged tocommence the withdrawing action of the casting from the mold. At thelower end or downstream end of the additional section the continuouscasting, pressure rollers and/or frames 9 are positioned at spacedlocations intermediate to the ends of the roller track 2 and itsadditional section 3.

3 from the mold, a pair of driving rolls 4 are provided to be formed. Onthe radially outer side of the roller track-Z-and additional section 3,a row of spaced fixed rollers 8 are rigidly mounted and form a supportfor the starting bolt and subsequently serve to support the continuouscasting as it is withdrawn downwardly from the mold 1 along the rollertrack. On the radially inner side of the roller track a plurality ofrollers 7 are spaced for contact with the other face of the continuouscasting as it moves through the roller track 2. If the withdrawing forcefrom the rolls 4 was applied to the bolt portion 5 of the withdrawinghead and bolt positioned between the rollers 7, and 8, the radiallyinner face of the bolt As the starting head and bolt withdraws thecontinuous casting from the mold, the pressure rollers 9 press the boltportion 5 against the rollers 8 located along the opposite surface ofthe bolt portion. Further, the withdrawing bolt portionS can be moved inthe opposite direction by the pressure rollers 9 in a particularlyaccurate manner for positioning it relative to the continuous castingmold l, a driving member 9a is associated with each pressure roller 9for driving the withdrawing head and bolt along the supporting rollertrack in the direction opposite to the withdrawing direction andinserting it into the mold. However, as soon as the continuous castingis withdrawn from the mold and its leading end approaches the first oneof the pressure'rollers 9, the rollers are set to the dimension of thecontinuous casting automatically by means of hydraulic pressure or byother means. After the leading end of the casting passes through thefirst one of the pressure rollers 9 the other pressure roller 9 remainsin contact with the bolt portion 5 and as the continuous castingapproaches the second pressure roller it also opens automatically byhydraulic pressure so that the continuous casting can pass between itand the oppositely disposed roller 8. This arrangement of, pressurerollers is highly suitable for transmitting a selected feeding force tothe casting in the regions where the casting has only a thin shellforming its exterior surface. This is particularly true when thepressure rollers are driven.

While 'a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. Apparatus for supporting a withdrawing head and bolt used incommencing the withdrawal of a continuous casting from a mold in anarcuate, deflecting or vertical continuous casting plant where the boltportion of the withdrawing head and bolt has a cross-section andthickness dimension smaller than the corresponding cross-section andthickness dimension of the continuous casting where the thicknessdimension is'the dimension between the supported surfaces of thecontinuous casting and the head portion of the withdrawing head and boltis in engagement with the continuous casting and includes a supportingroller track set to receive the cross-section of the continuous casting,said supporting roller track includes a plurality of first rollersspaced apart in the direction of travel of the continuous casting andarranged to form a fixed support along one side of the continuouscasting, and a plurality of second rollers spaced apart in the directionof travel of the continuous casting and arranged on the opposite side ofsaid roller track from said first rollers in the direction of thethickness dimension of the continuous casting and said second rollersarranged to contact the opposite side of the continuous casting from theside contacting said first rollers, and a pair of driving rolls locatedat the downstream end of said roller track for withdrawing thewithdrawing head and bolt and the continuous casting from the mold alongsaid roller track, wherein the improvement comprises a plurality ofpressure rollers spaced between at least certain of said second rollersand located on the same side of said roller track as said secondrollers, said pressure rollers are adjustable in the direction towardsaid first rollers relative to the smallest cross-sectional area of thevariable cross-sectional area of the withdrawing head and bolt and arepositionable inwardly from said second rollers toward said first rollersfor contacting and applying pressure directed toward said first rollersand against the bolt portion of the withdrawing head and end of themold.

1. Apparatus for supporting a withdrawing head and bolt used incommencing the withdrawal of a continuous casting from a mold in anarcuate, deflecting or vertical continuous casting plant where the boltportion of the withdrawing head and bolt has a crosssection andthickness dimension smaller than the corresponding cross-section andthickness dimension of the continuous casting where the thicknessdimension is the dimension between the supported surfaces of thecontinuous casting and the head portion of the withdrawing head and boltis in engagement with the continuous casting and includes a supportingroller track set to receive the cross-section of the continuous casting,said supporting roller track includes a plurality of first rollersspaced apart in the direction of travel of the continuous casting andarranged to form a fixed support along one side of the continuouscasting, and a plurality of second rollers spaced apart in the directionof travel of the continuous casting and arranged on the opposite side ofsaid roller track from said first rollers in the direction of thethickness dimension of the continuous casting and said second rollersarranged to contact the opposite side of the continuous casting from theside contacting said first rollers, and a pair of driving rolls locatedat the downstream end of said roller track for withdrawing thewithdrawing head and bolt and the continuous casting from the mold alongsaid roller track, wherein the improvement comprises a plurality ofpressure rollers spaced between at least certain of said second rollersand located on the same side of said roller track as said secondrollers, said pressure rollers are adjustable in the direction towardsaid first rollers relative to the smallest cross-sectional area of thevariable cross-sectional area of the withdrawing head and bolt and arepositionable inwardly from said second rollers toward said first rollersfor contacting and applying pressure directed toward said first rollersand against the bolt portion of the withdrawing head and bolt as itmoves through said roller track, each said pressure roller beingindividually releasable for removing said pressure roller from contactwith the withdrawing head as the head Portion of the withdrawing headand bolt begins to pass said pressure roller, and said pressure rollersincluding means for driving the withdrawing head and bolt along saidsupporting roller track in the direction opposite to the direction ofwithdrawal of the continuous casting for inserting the head portion ofthe withdrawing head and bolt into the outlet end of the mold.